List and Strings

A string is a sequence of characters and a list is a sequence of values, but a list of characters is not the same as a string. To convert from a string to a list of characters, you can use list:

>>> s = 'spam'
>>> t = list(s)
>>> print t
['s', 'p', 'a', 'm']
>>> type(s)

>>> type(t)

List is the name of a built-in function, you should avoid using it as a variable name. The function of list method is to break string into individual letters. If you want to break string into words, you can use the split method:

>>> s = 'Say hello to my little friend'
>>> t = s.split()
>>> print t 
['Say', 'hello', 'to', 'my', 'little', 'friend']
>>>print t[2]
Hello

Once you have used split to break the string into a list of tokens you can use the index operator to look at a particular word in the list. You can also split the words from string which are ‘connected’ using the ‘_’ or ‘-‘ character (or any other character). First thing you need to specify what character you want to remove from a string and store it as a variable and then pass it as an argument to split method.

>>> s = 'Say-hello-to-my-little-friend'
>>> rem = '-'
>>> t = s.split(rem)
>>> t
['Say', 'hello', 'to', 'my', 'little', 'friend']

Opposite to split method Python has join method. This method takes a list of strings and concatenates the elements.

>>> t
['Say', 'hello', 'to', 'my', 'little', 'friend']
>>> ad = ' '
>>> ad.join(t)
'Say hello to my little friend'

In this case the delimiter is a space character, so join puts a space between words. To concatenate strings without spaces, use the empty string as adding attribute.

>> t
['Say', 'hello', 'to', 'my', 'little', 'friend']
>>> ad = ''
>>> ad.join(t)
'Sayhellotomylittlefriend'